package javaBase.nowcoder.HJ10_B_字符个数统计;

import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        String tem = "";
        for (int i = 0; i < s.length(); i++) {
            if (0 <= s.charAt(i) && s.charAt(i) <= 127 && tem.lastIndexOf(s.charAt(i)) == -1) {
                tem += s.charAt(i);
            }
        }
        System.out.println(tem.length());
    }
}
